European patent EP 0 317 518 discloses a device for protecting a syringe needle, which device comprises a protective case and a resilient ring having two diametrically-opposite coaxial extensions, one of the extensions forming an integral portion of one end of the protective case, and the other extension forming an integral portion of a nut connected to one end of the body of the syringe. The structure of that prior protective device is suitable for only one type of syringe, and the device is relatively complex to put into place on the syringe.